-444 TUBERCULOSIS. 



In addition to the above-described changes taking place in 

 the neighborhood of the encysted or disintegrated foci, morbid 

 processes occur in the rest of the lung-tissue, most intense, as a 

 rule, in the upper lobes, while the lower lobes are comparatively 

 little affected. In more or less extensive districts, isolated nod- 

 ules, the size of a poppy- or millet- or hemp-seed, are observed ; 

 first as gray, gelatinous dots in the lung-tissue, this being satur- 

 ated with a viscid, albuminous exudation. Starting from their 

 -centers, the nodules then assume a grayish-yellow color, after- 

 ward become yellow, and are finally transformed into a cheesy, 

 crumbly mass, before a capsule or callosity has formed in the 

 vicinity. While the old nodules take part in this metamorphosis, 

 fresh gray ones arise, so that we often find in the same lung 

 all transitions, from the gray to the yellow, and disintegrated 

 tuberculous nodule. Sometimes the nodules are grouped around 

 a bronchus in a wreath-like arrangement (Peribronchitis nodosa, 

 Buhl), or they may appear first at the periphery of a lobule which 

 is in the condition of a flabby, red, or grayish-red hepatization. 

 They may also fill the whole lobule, retaining their nodular form 

 as long as no disintegration has taken place. 



Sometimes only scattered nodules are met with in the diseased 

 lung; sometimes nodules are combined with infiltrations; and 

 sometimes only infiltrations present themselves, which consist of 

 grayish-yellow, firm, half -dry foci, ranging in size from that of a 

 lentil to that of a hazel-nut, such as I have described as occurring 

 in chronic tuberculosis. 



The infiltrations become disintegrated into a friable, crumbly 

 mass. This disintegration always starts from the centers of the 

 diseased parts. The view held by older pathologists, and also 

 by Virchow, is that the softening is a chemical process, occur- 

 ring, perhaps, independently of any imbibition of water from 

 without. This idea of a melting process taking place, as it were, 

 in the own liquid, follows from the belief that the infiltration 

 from its very outset appears of a certain size, and retains this 

 size until " melted' 7 or transformed to " softened cheese." A 

 different explanation may be obtained if we remember the fact that 

 the node at its periphery continues enlarging, and that the oldest 

 focus of disease is to be looked for at the place where the soften- 

 ing starts. The tuberculous mass, therefore, may have become 

 soft by liquid derived from the inflamed neighboring parts before 

 peripheral new production has occurred, which still exists in the 

 " cheesy " stage. 



